Today we would like to introduce to you a new member of the successful Raptor
hard disk drive family from Western Digital. This new HDD with 150GB storage capacity demonstrated superior performance in
a single-user environment. Besides, it features a unique design peculiarity вЂ“
transparent clear case top that allows you to see whatвЂ™s going on inside. Read
more about this extremely successful product in our detailed review

ItвЂ™s not easy to get back to business again, but I canвЂ™t help that because Western
Digital at last released its new Raptor! I personally have long been waiting for
it. Hard drives with a spindle rotation speed of 7200rpm were increasing their
storage capacity at a rapid rate to 200, 300, 400 and now to as much as 500
gigabytes! And the problem of choice between a Raptor and an ordinary drive but
with five times the capacity was getting ever harder to solve.

But now Western Digital reminds us about itself once again with its Raptor
150GB. To be exact, there are two new drives with 150GB storage capacity. One of
them is quite an ordinary but larger Raptor, while the otherвЂ¦ Well, the other
can store 150GB of data too, but it has a striking appearance due to a
transparent window in its case through which you can watch the read/write heads
working. I donвЂ™t recommend doing that for more than 15 minutes per day. ItвЂ™s
just hypnotizing!

So this model with a transparent window has got a unique name, Raptor X, and
even a personal
website where you can learn about its development and read its tech specs,
see some photos, etc.

And so it happened that it was a Raptor X that dropped in on our labs
first.

Closer Look: Raptor X

So, here it is:

The window that you can have a peep inside the drive through is shaped
irregularly, but the fastening of the platters block and the actuator and even,
partially, the top read/write head can be seen quite well.

Western Digital remains true to its tradition of placing the electronics board
with the chips facing inward. You may note one detail missing here вЂ“ there is no
ATA-SATA converter chip on the visible side of the board. But itвЂ™s all right.
The chip shouldnвЂ™t be there because the drive features a native SATA interface.

As you see, the PCB has only three microchips: processor, memory chip and
motor controller chip.

Also you can see two acceleration sensors in the top corners of the PCB.
Accelerometers of the drive measure the vibration levels and corrects the
current disk operations.

By the way, about that windowвЂ¦ Some three years ago a hard disk drive with a
window was fabricated in our laboratories. I do not claim it was the worldвЂ™s
first device of such a kind (IвЂ™m old enough to remember the transparent cases
with a pack of 5MB platters as the disk subsystem of an IBM/360), but we seem to
have made it ahead of Western Digital:

In our quarrelsome times this may be enough for a legal suit, but we are not
sure if we ourselves are to bring an action against WD or should be preparing
against one instead. :)

But letвЂ™s get closer to serious matters now. Hard disk drives of the Raptor
series have to meet tough requirements in the market sector Western Digital
positions them into. HDDs that are to replace SCSI drives in workstations and
entry-level servers must be fast, reliable and cheaper. The price
factor isnвЂ™t a problem at all. Raptor drives cost less than SCSI ones and do not
require an expensive controller (in fact, the controller is usually integrated
into the mainboard and is absolutely free). The speed characteristics of the new
Raptor are what we are going to explore throughout this review. Reliability is a
difficult question of course, but the second generation of Raptor drives seemed
to me more reliable than the first. I hope the third generation is going to be
even better in this respect.

And now letвЂ™s take a look at the specs:

The new model boasts two times the storage capacity of the older one (so it can store
150GB now), a cache buffer for 16 megabytes, and support for NCQ technology. The speed of data transfers from the
driveвЂ™s buffer to the host controller has remained the same at 150MB/s. ThatвЂ™s
not a cause for grumbling since this parameter is not at all crucial for the
driveвЂ™s performance.

The HDD supports Western DigitalвЂ™s exclusive technologies called TLER
(Time-Limited Error Recovery) and RAFF (Rotary Acceleration Feed Forward). The
former is meant to improve reliability of the error-correction algorithms in
RAID arrays, while the latter improves the performance of the drive when under
vibration.

Test and Methods For The Raptor X

ItвЂ™s the first time I am going to use our new testbed for hard disk drive
tests. EverythingвЂ™s changing and we canвЂ™t resist the progress.

We got dissatisfied with the old testbed due to the fact that we had built it
exactly like an average computer system of that time. And our testbed has
remained intact all through the following time, through the change of chipsets,
processor sockets, memory types, etc. On one hand, that was good because we
could accumulate a large database of results for comparison and analysis, but on
the other hand, we were getting each day farther from the average computer
configuration of our readers (or rather, our readersвЂ™ computers were getting
more and more advanced in comparison with our testbed) and the results of our
tests were beginning to lose touch with reality.

When we were selecting benchmarks to be used in tests of hard drives on our
site, we did try to stick to those of them which did not depend much on the CPU
performance or the amount of system memory. And our trial runs of the new
platform have showed that the hardware configuration has a much smaller effect
on the test results than the operating system used.

Yes, the main innovation of the new testbed is the operating system installed
on it вЂ“ Windows XP SP2. Unfortunately, we didnвЂ™t make it to Vista because the
implementation of the new WinFS file system in the OS known under the codename
of Vista has been postponed for an indefinite period of time.

And this is how our new testbed is configured:

Foxconn 945G7MA-8EKRS2 (i945G + ICH7R) mainboard

Intel Pentium 4 521 CPU (2.8GHz, 800MHz FSB)

IBM DTLA-307015 15GB system hard disk drive

Radeon X300 128MB graphics card

512MB DDR2-533 SDRAM

Microsoft Windows XP SP2

The hard drives were tested on a Promise SATA-II 150 TX2 Plus controller:

This way we put hard disk drives with ATA and SATA interfaces under the same
conditions since the employed controller supports both interfaces. The reason
why we took an external controller at all is quite simple. Thanks to Intel,
thereвЂ™s only one connector for PATA drives on mainboards based on the i945+ICH7R
chipset and this connector has to be occupied by the system HDD.

The following benchmarks are used in our tests:

Intel IOMeter 2003.02.15

PCMark05 Build 1.1.0

WinBench 99 2.0

FC IOMark 03b15

FC-Test 1.0 build 13

FC-Test 2.0 build 1005

The tested drives are formatted in FAT32 and NTFS as one partition with the
default cluster size. In some cases mentioned below we used 32GB partitions
formatted in FAT32 and NTFS with the default cluster size.

Average Read/Write Response Time benchmark test

The first test in this review is meant to check the average response time of
a hard disk drive at reading/writing random sectors.
The goal of the test is to measure the disk access time at reading and see how
aggressive the drivesвЂ™ deferred write policy is (roughly speaking, we are going
to see how many segments are allocated in the driveвЂ™s cache for storing write
requests).

So we make IOMeter send a stream of requests to read and write 512-byte data
blocks with the request queue depth set at 1 for 10 minutes. The total number of
requests processed by the drive is over 60 thousand. This ensures we get a
sustained disk response time in the end, which doesnвЂ™t depend on the size of the
driveвЂ™s cache buffer.

Here are the results of the drives in IOps (the number of requests processed
per second). The more requests the drive manages to process, the faster the
drive is, as you can easily guess.

The two WD740GD clearly use different read-ahead policies. More interesting
is that they also take different approaches to processing write requests! The
WD1500AHFD is in between them in reading speed, but is far faster than both the
WD740GD at processing write requests. Well, it would have been strange if it had
done otherwise having twice the amount of cache memory.

The results can be translated from IOps into traditional parameters вЂ“ read
and write response time.

The results themselves do not change, of course. They are just represented in
a different way.

IвЂ™ll soon get back to examining the drivesвЂ™ behavior at processing random
read and write requests. Right now letвЂ™s check the speed of reading from and
writing into the driveвЂ™s cache buffer.

Burst Rate raptor x benchmark test

There are a lot of benchmarks to measure the speed of reading from the
driveвЂ™s buffer, but unfortunately few of them are free from certain
deficiencies. For example, the burst rate may be measured using small-size data
blocks (in compliance with the old ATA/ATAPI specifications). Or the number of
iterations may be dubious, too.

The Raptor X is obviously better than the previous-generation drives in this
parameter, especially when it comes to writing into the buffer.

NCQ vs. TCQ

After all is said and done, the main and most intriguing feature of this
review is the new hard disk driveвЂ™s support for Native Command Queuing technology.

Western DigitalвЂ™s Raptor drives used to support only the so-called legacy ATA
queuing. And WDвЂ™s market opponents would regard the word legacy as
synonymous with obsolete or archaic , promoting NCQ instead. But
you may remember that even that old and archaic technology did quite well in our
tests.

But now that the Raptors have acquired support for the most progressive
commands-reordering technology, the competitors cannot really blame Western
Digital (except for the companyвЂ™s growing profits :)).

The WD740GD drives support Tagged Command Queuing (TCQ) whereas the Raptor X
features NCQ. The Promise S150 II TX2+ controller supports both the versions of
this technology, thus giving an opportunity of an all-around comparison.

As usual, I use IOMeter to bombard the drive with a stream of requests to
read random-address sectors while steadily increasing the length of the request
queue. Thus, the controller has an opportunity to send independent
commands to the drive (commands whose result doesnвЂ™t affect the queuing or
processing of other commands).

Can it be that NCQ just doesnвЂ™t work in the new drive? Or maybe the controller
doesnвЂ™t send it the вЂњmagicвЂќ commands? On the other hand, thereвЂ™s a definite
performance growth as the outstanding requests queue is getting longer and the
graph has a characteristic shape at loads of up to 32 requests, too

As you can see, the graphs are similar irrespective of the status of NCQ. So
I think this proves that NCQ doesnвЂ™t work for write operations. But maybe it
doesnвЂ™t work in this particular drive only? No. We tested a few SATA300 drives
from different manufacturers and they were always behaving like the WD1500AHFD
at high percentages of write operations.

But whence comes this dislike towards random-address writes? Why are they not
put into the common queue? I think the answer is very simple. It isnвЂ™t
profitable. I mean you donвЂ™t get any performance gains by that.

And well, why should you be pushing write requests into the narrow bottleneck
of the 32-commands-big buffer when there is a huge cache buffer at your disposal!

It means that when the drive is receiving write requests, it just stacks them
down in the cache and reports a completed operation without yet writing anything
to the platter! It is going to be a very, very fast drive from an outside
observerвЂ™s point of view.

Generally speaking, deferred writing is a very helpful feature of all modern
hard drives for desktop computers, and it is largely due to the
ever-improving algorithms of adaptive deferred writing that the performance of
hard drives is getting higher year after year. A modern HDD already comes
equipped with as much as 16 megabytes of cache memory and may call for even more
in the future. Even half that size (supposing one half of the cache is allocated
to look-ahead reading and auxiliary tables) can store as many as 16384 sectors
if necessary.

Of course, no one is going to create so many cache segments. The more
segments there are, the bigger the overhead is. Suppose we know where the
driveвЂ™s heads are right now and we are to find out the processing order for the
deferred write requests. The more segments there are in the buffer, the more
time it is going to take to calculate the optimal order.

Anyway, the number of buffer segments allotted for deferred writing is over
32 in modern hard disk drives, so there is no sense for them to use the Write
FPDMA Queued mechanism. And they just do not use it! :)

I can show you the results of a Maxtor drive with a 16MB buffer as an
illustration of one funny side effect of this. The graph below shows the
dependence of the MaxtorвЂ™s random read and write speeds on the data block size

Do you see that strange hump at the beginning of the write graph? ItвЂ™s
because the drive found out that it was being bombarded with small
random-address requests and tried to withstand the DoS attack by collecting the
requests into its cache. I donвЂ™t know how many cache lines it opens up at that,
but the solution looks very elegant. Such a logical caching
strategy of MaxtorвЂ™s drives has even misled some reviewers into confusing access
time with seek time :).

But letвЂ™s get back to the subject of our review again. In this section weвЂ™ve
found out that the WD1500AHFD-00RAR0 hard disk drive does support NCQ
technology.

At the same time, the speed characteristics of the Raptor X at high loads are
worse than those of the previous-generation drive from WD. I should also
acknowledge the fantastically high speed of the WD740GD-FLC0 drive (this must be
a special, server-oriented version of that drive modelвЂ¦)

I donвЂ™t claim yet that NCQ hasnвЂ™t proved its superiority over TCQ. After all,
IвЂ™ve only tested one drive so far.

Performance in Intel IOMeter raptor x benchmark test

Random Read/Write

As I promised above, IвЂ™m going to discuss the drivesвЂ™ speeds at processing
random read/write requests at more length now.

At first I showed you how the new Raptor reacts to random requests the size
of a sector, i.e. 512 bytes. But what if the data block is larger? We may see some anomaly or, if
there is none, we just get the dependence of the random read/write speed on the
size of the data block. The drives may even end up doing linear reading.

A general observation from the two diagrams above is like follows: random
reading/writing does not transform into linear operations even when 32MB data
blocks are processed.

Sequential Read/Write raptor x benchmark test

ItвЂ™s all simple here. The drive is receiving a stream of requests to read and
write data blocks. The addresses of the data blocks are
sequentially increasing. Once in a minute the size of the data block is changed
so that we could see how the linear read/write speed depends on the data block
size

ThereвЂ™s only one thing to be said: the WD740GD drives are no match for the
Raptor X when it comes to sequential reading/writing. Its advantage over them at
writing small data blocks is most impressive (remember the Write Burst Rate
graphs?)

Next goes a very interesting test that measures the driveвЂ™s performance in
multi-threaded environments

Multi-Threaded Read/Write raptor x benchmark test

Unlike our colleagues, we do not use NBench for explorations of that kind.
Since modern hard drives come with as much as 16 megabytes of cache memory, we
need a means to force as big an amount of data through the driveвЂ™s cache as to
minimize the measurement error due to deferred writing. NBench would be always
reporting a write speed higher than the linear read speed because the drive
reports an end of a write operation before the tail of the file in the cache is
actually written on the platter.

So, we use IOMeter instead and run it as long as to exceed the driveвЂ™s cache
buffer in two times at least. We create four simultaneously running threads (an
individual worker , each with its own portion of disk space to operate
in, is responsible for each of the threads). The disk is accessed by 64KB blocks
and the outstanding requests queue depth is steadily changing from 1 to 8.

The diagrams below show the results for the queue length of 1 as
representative of the typical load on the disk subsystem of a desktop computer.

The case with one thread is in fact synonymous with linear reading from the
disk. ItвЂ™s no wonder then that the two WD740GD have identical results and the
WD1500AHFD is much faster than them.

ItвЂ™s different when there are two threads to be processed. The WD1500AHFD is
still in the lead while the two WD740GD models have split up. The вЂњwildвЂќ
WD740GD-FLC0 is suddenly much slower than its brother. This is the consequence
of its optimization for random operations and of its reluctant look-ahead
reading.

Workstation raptor x benchmark test

The results of the WD1500AHFD are considerably better in this test. I wonder
how this is going to affect its overall performance rating which we calculate by
the following formula:

As you can see from the formula, smaller loads have greater weights in the
overall result because they are more typical of a workstation.

And hereвЂ™re the ratings weвЂ™ve got:

Thanks to its higher speed under low loads, the WD1500AHFD has got higher
ratings irrespective of how much of the driveвЂ™s storage space is in use.

PCMark05 raptor x benchmark test

And now I will try to evaluate the performance of the drives using
FuturemarkвЂ™s PCMark05. Besides everything else, this benchmark includes a set of
hard disk drive tests. The tests are simple: the user can run the drive along a
prefabricated trace. A trace is in fact a log of access to some вЂњdefaultвЂќ hard
disk drive which was mercilessly tested in FuturemarkвЂ™s laboratories.

The benchmark offers five traces in total:

XP Startup

Application Loading

General Usage

Virus Scan

File Write

The tests can be run separately or all in a batch. I chose the second option,
perhaps wrongly.

The fact is each decent hard disk drive wants to be a вЂњblack boxвЂќ. And it
wants to be a block box that reacts to a request on its input depending on the
entire history of earlier requests. By running the tests in a batch, we pass the
drive through all the traces one by one. It doesnвЂ™t have time enough to get used
to one trace, but we already start another.

On the other hand, it would be strange to run the XP Startup trace a dozen of
times because it is assumed that the booting of the OS is done after a cold or
warm restart of the computer, and at this moment the hard drive is
reinitialized, i.e. the accumulated access statistics is cleared and the drive
is reset into some вЂњinitialвЂќ state.

Anyway, the test conditions were the same for all the participating devices,
so we can compare the results.

So, the WD1500AHFD is again on top. The вЂњwildвЂќ WD740GD can provide some
competition to it on the XP Startup trace, but on all the other traces the
Raptor X is unrivalled.

IвЂ™m rather doubtful about the results of the drives on the Virus Scan and
File Write traces because the measured speed of the drives is higher than they
can physically do.

Conclusion of our test

In this review we have thoroughly explored the new hard disk that Western Digital targets at computer
enthusiasts, the people who want to have the most advanced and fastest
components in their systems. ItвЂ™s none of my business whether they actually need that speed. My
goal was to see how well the Raptor X suits the market niche WD is promoting it
into.

And hereвЂ™s my verdict вЂ“ by all 100 percent and more! Each and every of our
tests shows that the Raptor X is sharpened for work in a single-user environment
in which it really looks much better than its closest opponents. Yes, it didnвЂ™t
have too many opponents in this review, but not because I was too lazy to test
them. I just wanted to save the reputation of the companies who donвЂ™t yet have
products similar to WDвЂ™s Raptor! :)

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